A signal processing system of a multiplexed FBG sensor using CDMA includes a
pseudo
random bit sequences (PRBS) generator for generating pseudo random bit sequence;
a LED for light-emitting at a pseudo random bit from the PRBS generator; a fiber
coupler for transmitting a light signal from the LED into a FBG sensor portion
and passing signals reflected by the FBG sensor portion herethrough; the FBG sensor
portion for receiving/reflecting the light signal via an optic fiber to forward
it back to the fiber coupler; an FBG filter portion for filtering the signal reflected
by the FBG sensor portion and passed through the fiber coupler; photo detector
for converting the light signal from the FBG filter portion into the electrical
signal; a delaying portion for delaying a pseudo random bit signal from the PRBS
generator for a predetermined time period; a mixing portion for mixing the delay
signal from the delaying portion and the output signal from the photo detector;
and at least one auto-correlation device for integrating or auto-correlating the
signal from the mixing portion, thereby enhancing the stability of the system and
the linearity of a signal to be measured to applied strain.
